Bottom Line:
Increased density of macrophages was associated with advanced stage and poor survival.AKT but not ERK regulated β-catenin translocation.Macrophages may induce invasiveness by activating the β-catenin pathway.

Affiliation: Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan.

ABSTRACT

Background: Despite evidence that activated macrophages act in an inflammatory microenvironment to promote gastric tumorigenesis via β-catenin signaling, the effects of β-catenin signaling on gastric cancer cell metastasis and the relationship of these cells with surrounding tumor associated macrophages have not been directly studied.

Methods: Immunohistochemical staining was employed to analyze 103 patients. An invasion assay was used to evaluate the relationship between macrophages and gastric cancer cells. β-catenin gain-of-function and loss-of-function approaches were performed. To assess the β-catenin regulation mechanism in gastric cancer cells, Western blotting and reverse-transcription polymerase chain reaction were used.

pone.0134122.g001: Immunohistochemistry analysis.Immunostaining against CD68 was performed on tissue slides from gastric cancer patients. CD68+ macrophage staining was sparse in the normal gastric mucosa (A). CD68+ cells were detected in both the stroma and tumor nest (B & C). The density of CD68+ macrophages in pathological tumor staging (pT) 1 (D) and pT4 (E) tumor lesions.

Mentions:
Immunohistochemical analysis showed a cytoplasmic CD68 staining pattern for macrophages. CD68+ macrophages were distributed throughout peritumoral and intratumoral tissues but only sparsely scattered in the normal mucosa (Fig 1A–1C). The density of CD68+ macrophages was especially high in pathological tumor stage 4 (pT4) tumor lesions compared with pT1 lesions (Fig 1D). To determine the association between clinical characteristics and CD68+ macrophage density, counts of CD68+ macrophages were divided into those above and below the median values. The number of CD68+ macrophages was found to be associated with tumor depth and stage (p = 0.001 and p = 0.043, respectively) (Table 1). This observation suggests that CD68+ macrophages may be important in promoting tumor invasion. For further analysis, Kaplan-Meier survival curves were plotted to determine the association of macrophages with survival (Fig 2). The density of CD68+ macrophages in the tumor tissue was negatively associated with overall survival (p = 0.0073). Patients with high numbers of tumoral CD68+ macrophages had shorter overall survival than those with low numbers of CD68+ macrophages.

pone.0134122.g001: Immunohistochemistry analysis.Immunostaining against CD68 was performed on tissue slides from gastric cancer patients. CD68+ macrophage staining was sparse in the normal gastric mucosa (A). CD68+ cells were detected in both the stroma and tumor nest (B & C). The density of CD68+ macrophages in pathological tumor staging (pT) 1 (D) and pT4 (E) tumor lesions.

Mentions:
Immunohistochemical analysis showed a cytoplasmic CD68 staining pattern for macrophages. CD68+ macrophages were distributed throughout peritumoral and intratumoral tissues but only sparsely scattered in the normal mucosa (Fig 1A–1C). The density of CD68+ macrophages was especially high in pathological tumor stage 4 (pT4) tumor lesions compared with pT1 lesions (Fig 1D). To determine the association between clinical characteristics and CD68+ macrophage density, counts of CD68+ macrophages were divided into those above and below the median values. The number of CD68+ macrophages was found to be associated with tumor depth and stage (p = 0.001 and p = 0.043, respectively) (Table 1). This observation suggests that CD68+ macrophages may be important in promoting tumor invasion. For further analysis, Kaplan-Meier survival curves were plotted to determine the association of macrophages with survival (Fig 2). The density of CD68+ macrophages in the tumor tissue was negatively associated with overall survival (p = 0.0073). Patients with high numbers of tumoral CD68+ macrophages had shorter overall survival than those with low numbers of CD68+ macrophages.

Bottom Line:
Increased density of macrophages was associated with advanced stage and poor survival.AKT but not ERK regulated β-catenin translocation.Macrophages may induce invasiveness by activating the β-catenin pathway.

Affiliation:
Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan.

ABSTRACT

Background: Despite evidence that activated macrophages act in an inflammatory microenvironment to promote gastric tumorigenesis via β-catenin signaling, the effects of β-catenin signaling on gastric cancer cell metastasis and the relationship of these cells with surrounding tumor associated macrophages have not been directly studied.

Methods: Immunohistochemical staining was employed to analyze 103 patients. An invasion assay was used to evaluate the relationship between macrophages and gastric cancer cells. β-catenin gain-of-function and loss-of-function approaches were performed. To assess the β-catenin regulation mechanism in gastric cancer cells, Western blotting and reverse-transcription polymerase chain reaction were used.